cerc-io/solidity
16
0
Fork 0
mirror of https://github.com/ethereum/solidity synced 2023-10-03 13:03:40 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Only allow access to local variables and only if they have a stack size of one.

Browse Source
This commit is contained in:
chriseth 2017-04-11 21:12:17 +02:00
parent f19e6a09a7
commit dfaab73efe
3 changed files with 53 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
libsolidity/analysis/TypeChecker.cpp
View File

@ -25,6 +25,7 @@
#include <boost/range/adaptor/reversed.hpp>
#include <libsolidity/ast/AST.h>
#include <libsolidity/inlineasm/AsmAnalysis.h>
#include <libsolidity/inlineasm/AsmData.h>
using namespace std;
using namespace dev;
@ -637,50 +638,59 @@ bool TypeChecker::visit(InlineAssembly const& _inlineAssembly)
auto ref = _inlineAssembly.annotation().externalReferences.find(&_identifier);
if (ref == _inlineAssembly.annotation().externalReferences.end())
return size_t(-1);
size_t valueSize = size_t(-1);
Declaration const* declaration = ref->second.declaration;
solAssert(!!declaration, "");
if (auto var = dynamic_cast<VariableDeclaration const*>(declaration))
{
if (!var->isLocalVariable())
{
typeError(_identifier.location, "Only local variables are supported.");
return size_t(-1);
}
if (var->type()->dataStoredIn(DataLocation::Storage))
{
typeError(_identifier.location, "Storage reference variables are not supported.");
return size_t(-1);
}
if (var->type()->sizeOnStack() != 1)
{
typeError(_identifier.location, "Only types that use one stack slot are supported.");
return size_t(-1);
}
if (var->isConstant())
{
typeError(_identifier.location, "Constant variables not supported by inline assembly.");
return size_t(-1);
}
}
else if (_context == assembly::IdentifierContext::LValue)
{
typeError(_identifier.location, "Only local variables can be assigned to in inline assembly.");
return size_t(-1);
}
if (_context == assembly::IdentifierContext::RValue)
{
solAssert(!!declaration->type(), "Type of declaration required but not yet determined.");
if (dynamic_cast<FunctionDefinition const*>(declaration))
valueSize = 1;
else if (auto var = dynamic_cast<VariableDeclaration const*>(declaration))
{
if (var->isConstant())
fatalTypeError(SourceLocation(), "Constant variables not yet implemented for inline assembly.");
if (var->isLocalVariable())
valueSize = var->type()->sizeOnStack();
else if (!var->type()->isValueType())
valueSize = 1;
else
// We cannot use `sizeOnStack()` here because we do not insert the value
// into inline assembly but rather the storage location.
valueSize = 2; // slot number, intra slot offset
}
else if (dynamic_cast<VariableDeclaration const*>(declaration))
{
}
else if (auto contract = dynamic_cast<ContractDefinition const*>(declaration))
{
if (!contract->isLibrary())
{
typeError(_identifier.location, "Expected a library.");
return size_t(-1);
valueSize = 1;
}
}
else
return size_t(-1);
}
else
{
// lvalue context
if (auto varDecl = dynamic_cast<VariableDeclaration const*>(declaration))
{
if (!varDecl->isLocalVariable())
return size_t(-1); // only local variables are inline-assembly lvalues
valueSize = size_t(declaration->type()->sizeOnStack());
}
else
return size_t(-1);
}
ref->second.valueSize = valueSize;
return valueSize;
ref->second.valueSize = 1;
return size_t(1);
};
assembly::AsmAnalyzer::Scopes scopes;
assembly::AsmAnalyzer analyzer(scopes, m_errors, identifierAccess);

48
libsolidity/codegen/ContractCompiler.cpp
View File

@ -557,33 +557,16 @@ bool ContractCompiler::visit(InlineAssembly const& _inlineAssembly)
else if (auto variable = dynamic_cast<VariableDeclaration const*>(decl))
{
solAssert(!variable->isConstant(), "");
if (m_context.isLocalVariable(variable))
{
int stackDiff = _assembly.deposit() - m_context.baseStackOffsetOfVariable(*variable);
if (stackDiff < 1 || stackDiff > 16)
BOOST_THROW_EXCEPTION(
CompilerError() <<
errinfo_sourceLocation(_inlineAssembly.location()) <<
errinfo_comment("Stack too deep, try removing local variables.")
);
for (unsigned i = 0; i < variable->type()->sizeOnStack(); ++i)
_assembly.append(dupInstruction(stackDiff));
}
else
{
solAssert(m_context.isStateVariable(variable), "Invalid variable type.");
auto const& location = m_context.storageLocationOfVariable(*variable);
if (!variable->type()->isValueType())
{
solAssert(location.second == 0, "Intra-slot offest assumed to be zero.");
_assembly.append(location.first);
}
else
{
_assembly.append(location.first);
_assembly.append(u256(location.second));
}
}
solAssert(m_context.isLocalVariable(variable), "");
int stackDiff = _assembly.deposit() - m_context.baseStackOffsetOfVariable(*variable);
if (stackDiff < 1 || stackDiff > 16)
BOOST_THROW_EXCEPTION(
CompilerError() <<
errinfo_sourceLocation(_inlineAssembly.location()) <<
errinfo_comment("Stack too deep, try removing local variables.")
);
solAssert(variable->type()->sizeOnStack() == 1, "");
_assembly.append(dupInstruction(stackDiff));
}
else if (auto contract = dynamic_cast<ContractDefinition const*>(decl))
{
@ -602,19 +585,16 @@ bool ContractCompiler::visit(InlineAssembly const& _inlineAssembly)
!!variable && m_context.isLocalVariable(variable),
"Can only assign to stack variables in inline assembly."
);
unsigned size = variable->type()->sizeOnStack();
int stackDiff = _assembly.deposit() - m_context.baseStackOffsetOfVariable(*variable) - size;
solAssert(variable->type()->sizeOnStack() == 1, "");
int stackDiff = _assembly.deposit() - m_context.baseStackOffsetOfVariable(*variable) - 1;
if (stackDiff > 16 || stackDiff < 1)
BOOST_THROW_EXCEPTION(
CompilerError() <<
errinfo_sourceLocation(_inlineAssembly.location()) <<
errinfo_comment("Stack too deep, try removing local variables.")
);
for (unsigned i = 0; i < size; ++i)
{
_assembly.append(swapInstruction(stackDiff));
_assembly.append(Instruction::POP);
}
_assembly.append(swapInstruction(stackDiff));
_assembly.append(Instruction::POP);
}
};
codeGen.assemble(

2
libsolidity/inlineasm/AsmAnalysis.cpp
View File

@ -141,7 +141,7 @@ bool AsmAnalyzer::operator()(FunctionalInstruction const& _instr)
success = false;
}
// Parser already checks that the number of arguments is correct.
solAssert(instructionInfo(_instr.instruction).args == _instr.arguments.size(), "");
solAssert(instructionInfo(_instr.instruction.instruction).args == int(_instr.arguments.size()), "");
if (!(*this)(_instr.instruction))
success = false;
return success;